Mark Krasnow

Administrative Appointments

• Investigator, Howard Hughes Medical Institute (1997 - present)
• Chair, Stanford University School of Medicine - Biochemistry (2006 - present)
• Executive Director, Wall Center for Pulmonary Vascular Disease (2010 - present)

Honors and Awards

• Fellow, American Academy of Arts & Sciences (2009)

Postdoctoral Advisees

Douglas Brownfield,  Andy Chang,  Astrid Gillich,  Peng Li,  Anna Lyuksyutova,  Fraser Tan,  Serena Tan

Internet Links

• Krasnow Lab

Current Research Interests

We are studying the biochemical mechanisms of cell migration, cytoplasmic extension, and cell adhesion during development of the Drosophila tracheal (respiratory) system. The tracheal system is a network of epithelial tubes that transports oxygen to the tissues, like the lungs and vascular system in mammals. We use a combined in vivo and in vitro approach, employing genetic, cellular, and molecular methods to identify and characterize genes involved in the processes, and reconstruction of the processes in simplified in vitro systems to study the functions of the identified gene products.

The development of the 80 cells in each segment that form the tracheal system has been characterized, and more than a dozen genes that regulate branch formation and outgrowth have been identified so far. Formation of the major tracheal branches is controlled by a homolog of mammalian fibroblast growth factors; it selects the positions where branches bud and guides the migration of tracheal cells during branch outgrowth via a receptor tyrosine kinase expressed on tracheal cells. We are trying to elucidate this FGF signaling pathway and understand how it controls cell migration. The fine terminal branches form by extension of long cytoplasmic processes from tracheal cells towards oxygen-starved tissues. This is regulated by chemotactic factor(s) secreted by hypoxic tissues. We have characterized several genes in this signaling pathway, and we are searching for the chemotactic factor. We wish to determine how the chemotactic factor and the other signaling components guide cytoplasmic outgrowth. We are also studying epithelial tube fusion, the process by which tracheal tubes from one segment find and fuse with tubes in the neighboring segments to connect up the tracheal network.

Publications

• Coronary arteries form by developmental reprogramming of venous cells. Red-Horse K, Ueno H, Weissman IL, Krasnow MA. Nature. 2010; 464 (7288): 549-53
• Dual origin of tissue-specific progenitor cells in Drosophila tracheal remodeling. Weaver M, Krasnow MA. Science. 2008; 321 (5895): 1496-9
• The branching programme of mouse lung development. Metzger RJ, Klein OD, Martin GR, Krasnow MA. Nature. 2008; 453 (7196): 745-50
• Social interactions among epithelial cells during tracheal branching morphogenesis. Ghabrial AS, Krasnow MA. Nature. 2006; 441 (7094): 746-9
• Branching morphogenesis of the Drosophila tracheal system. Ghabrial A, Luschnig S, Metzstein MM, Krasnow MA. Annu Rev Cell Dev Biol. 2003: 19 623-47